Does the Encoding of a Web Site Matter for Google?

In a Google Groups thread, a forum member worries that Google is spotting the wrong character encoding for his web site. In particular, he states that Google is finding that the site is US-ASCII rather than UTF-8.

JohnMu says that this is not a problem, however.

In general, especially for mostly English language content, there is no big difference since US-ASCII (7-bit ASCII) is a subset of UTF-8. English language content can be seen as either type, so it doesn't really matter which one we determine. Also keep in mind that while we trust that YOU ;) are able to give us the correct content-type, this is not always the case on the web in general, so sometimes we try to determine it ourselves. That could mean that we recognize it as being US-ASCII even though it could also be seen as UTF-8.

According to John, the only times he's encountered Google reporting wrong encoding was when there was an actual issue wrong with the site, so in other words, this should not be a serious issue.